1. Field
Indium-based quantum dots and production methods thereof are disclosed.
2. Description of the Related Art
Unlike bulk materials, nanocrystals have physical characteristics (e.g., energy bandgap and melting point) that are intrinsic properties based on their particle size. For example, a semiconductor nanocrystal (also known as a quantum dot) is a semiconductor material having a crystalline structure and a particle size of several nanometers. The semiconductor nanocrystal has a very small particle size and a large surface area per unit volume, and may exhibit a quantum confinement effect. Therefore, the semiconductor nanocrystal has different physicochemical characteristics than a bulk material having the same composition. For example, the quantum dot is capable of controlling its energy band gap depending on its size and composition, and may emit light having high color purity at different wavelengths. Therefore, the quantum dot may find utility in various fields such as displays, energy, a semiconductor, and biology, and thus draws a lot of attention.
The semiconductor nanocrystal may be synthesized by a vapor deposition method such as metal organic chemical vapor deposition (“MOCVD”) or molecular beam epitaxy (“MBE”), or by a wet chemical method which includes adding a precursor to an organic solvent to grow crystals. The wet chemical method produces a colloidal quantum dot (“CQD”), wherein organic materials, such as a dispersant, are coordinated to a surface of the semiconductor crystal during the crystal growth to control the crystal growth.
As a nanocrystal particle having a core-shell structure, some quantum dots including cadmium (Cd), lead (Pb), or mercury (Hg) are known to show enhanced luminous and photo-electric efficiency, but they also pose serious environmental threats due to the inclusion of these poisonous heavy metals. Therefore, it is desirable to develop quantum dots that do not include such heavy metals and show enhanced properties.